Construction of quality walkways, driveways, patios, pool decks, retaining walls and footers, garden perimeters, and other similar structures is a labor-intensive process, typically requiring a number of steps, each step subject to stringent quality and performance requirements. Failure to meet set standards can be frustrating and costly, often causing rework and accompanying delays.
Using conventional construction methods, a trench is first prepared to a depth that allows for specified thicknesses of particulate substrate material that serves as a base, such as gravel, small stones, and sand. This base, in turn, supports the finished paving materials at the proper height, usually at or near ground level. Finished paving materials that are then placed upon the base can include paving blocks, stones, or bricks, or may include poured concrete or other materials. The width of the trench is significantly larger than the width of the finished walkway or other structure due to the need to provide sufficient space for forms to be inserted, manipulated and supported along the sides of the trench. Requiring time and effort that are not seen in the finished product, the process for providing the needed excess width, termed over-digging by those skilled in the construction arts, is inherently wasteful.
To assist in the substrate lay-down process, forms inserted on both sides of the trench are used to contain the particulate substrate materials and also provide a reference for arranging the finished paving material. There are many types of forms that can be used, including wood, plastic and metal forms. Wooden forms can warp undesirably and are not generally reusable, flexible, or easy to install. Plastic forms serve only in lightweight applications and are not sturdy enough to withstand the rigors of the construction environment and not rigid enough to contain heavy materials or bear the weight of a screed. Metal forms are heavy, costly to replace, troublesome to assemble, and relatively inflexible, requiring careful cleaning after use to remove any affixed concrete.
The forms are anchored in place in a number of ways, using devices such as wooden stakes, rebar, or metal stakes devised for the purpose of anchoring forms so that they remain in place as the structure is assembled. Forms are fastened to the anchors using fasteners such as clips, nails, and spacers, for example.
Leveling the forms along any section of a walkway or other structure can be a difficult task. Mistakes or tolerance errors can be additive, further complicating the leveling process.
Once the forms are set in place, the trench or gap is leveled. The term “level” does not imply that the surface of the trench need be completely flat; the term “level” is used to denote creating a smoothed continuous surface without significant high or low areas to allow depositing a layer of substrate at an essentially uniform depth.
When the dirt in the trench has been leveled, the particulate material is deposited between the forms and also leveled. To achieve a uniform depth of material, the substrate material is typically tamped down with a vibratory plate compactor or by a hand compactor. In practice, application and leveling of the substrate material is accomplished by dumping or by sifting the material into the prepared trench from wheelbarrows or other construction machinery such as front loaders. The volume of material that is dumped at any one time is calculated to spread somewhat evenly and reduce excessive raking and handling.
Using the example of a walkway, gravel is deposited as a first or substrate layer. This is then spread and leveled. This process can begin and be assisted with construction machinery, but, as it progresses, typically requires hand leveling with rakes and screed bars to the desired depth. To provide a solid base, the gravel is tamped down with a vibratory plate compactor or by a hand compactor. The cycle of depositing material, spreading, and tamping is repeated with stone dust and sand or other particulates as required, until the surface is properly conditioned for bricks or other finish materials. When all the desired layers are in place, the finished layer of paving blocks, bricks or concrete is put in place to complete the walkway.
Although the process of surface preparation for a walkway or other structure is straightforward, the preparatory steps to prepare the support structures can be challenging. In practice, these steps are often redone, since accurate leveling at the desired depth for each layer is difficult. Thus, there is a need for improved apparatus and methods for preparation and conditioning of a support base for walkways, driveways, patios, pool decks, retaining walls and footers, garden perimeters, masonry, and other similar structures.
Proposed solutions for installation of materials for a walkway or other structure are less than satisfactory. For example:                (i) U.S. Pat. No. 6,866,239 to Miller et al. discloses a form assembly for forming a concrete structure during drying of the concrete. The form assembly is an elongated plastic form having a front wall for engaging the concrete, and a rear wall. The front wall is spaced apart from the rear wall to define a pocket for receiving at least one connecting member. The connecting member is secured in the pocket to project a distance beyond an end of the form. A slidable stake holder may also be provided to slide in a C-shaped pocket in the form. The stake holder has right and left flanges that abut against or engage the rear wall. At least one preformed nail hole is provided in each of the right and left flanges. The forms do not indicate desired depth of materials. Connecting members secured in the pockets render the form inflexible at the joint between forms. Unfortunately, the distance from the front wall of the form to the aperture in the sliding stake holder for holding a stake is fixed, making it difficult to set distance between forms on opposite sides of the walkway, complicating lateral placement of the form with the stake accurately placed. Additionally, the sliding stake holder is not fixably engaged with the form by a connector screw or clamp; as a result, sliding, possible while particulate materials are being added between forms, can result in errors.        (ii) U.S. Pat. No. 7,131,624 to Bogrett teaches flexible forms for creating landscape edging. However, stakes or positioning brackets used to secure the forms are not reusable, and additional spacers are needed to maintain the distance between forms, making it difficult or impractical to place paving blocks. Joining extensions are created from the same material as the forms and are not intended to be reusable and do not appear to facilitate accurate longitudinal adjoining of forms.        (iii) U.S. Pat. No. 6,021,994 to Shartzer teaches a flexible form for use in pouring concrete. Rigid core members are added to maintain strength but removed when flexibility is desired. Stakes protrude through the forms and connection to the form is made only via the rigid core members with nails, complicating the task of positioning the forms. Since the rigid core members are removed when the forms are bent, however, securing the stakes to the form is not possible.        (iv) U.S. Pat. No. 4,340,351 to Owens teaches a screed fabricated in modular fashion from a plurality of interconnected, separable frame units. Modular sections forming the screed can be connected to provide a convex or concave screed depending on the shape of the desired surface. However, the screed formed from modular sections is a complicated assembly, difficult to fabricate, and does not provide adjustment appropriate to the desired depth of layers of particulate material.        
There exists a need to improve the quality of tools used in creating layers of material for supporting particulate and finished paving materials which eliminate much of the expertise required for substrate preparation and reduce unnecessary rework.